Node.js spawn for command-line?
Try changing the child_process.spawn('blender', arguments); line to child_process.spawn('/Applications/blender/Blender.app/Contents/MacOS/blender', arguments);.  NodeJS won't be using your bash aliases, so unless the blender executable is in its PATH it won't be able to find the executable and will throw an ENOENT.

The other option is adjusting Node's PATH to include the path to the blender executable.  You could also pass the fullpath to the blender executable in as an environment variable.

Cheers!